Recuperator



C. L. W. TRINKS.

RECUPERATOR.

APPLICATION FILED AUG.28, 1919.

Patented June 1, 1920.

WIT N ESS To all whom it may concern:

UNITED." srArEs PATENT OFF-ICE.

. i l I CHARLES L. w.-'rn,1NKs, or PITTSBURGH, PENNSYLVANIA, AssIGNoRJmo Ta'rE-JoNEs- 1 & COMPANY, INCL, OF PITTSBURGH, PENNSYLVANIA ACORPORATION OF PENN- SYLVANIA.

Be it'knownthat I, CHARLES L. W.

'TRINKS, a resident of Pittsburgh, Allegheny county, Pennsylvania, have .invented a new and useful Improvement in Recuperators,of which the following is a full, clear, and exact description, reference being had to the accompan ing drawings, forming part. of this spec' cation, in which- Figure 1 is a sectional view, largely diagrammatic, illustratingone form of the application of my invention;

.is of great, importance.

relatively high temperatures recuperator is made of metal, the tempera Fig. 1 is a-view correspondingto Fig. 1,

illustrating a modified form of inven-j 15 tion;

Fig. 2 is a similarview showing another application of the invention; and Figs. 3, 4t and 5 are sections taken respectivel on the lines III-III, IV-IV and V of Fig. 2.

My invention has relation to recuperators.

designediforuse in furnace work, such as adapted to a wide variety of uses The utilization of as large a percentage as-possible of the heat which is ordinarily carried oif by the waste gases of a furnace The efliciency of many types of furnaces, I annealing furnaces, is known to be comparatively products of chamber combustion must leave the heatof the furnace at a temperature in excess of that of the material to be heated. Heretofore, and particularly where are concerned, it has been customary in practice to employ regenerators in order to utilize, as "far as possible, the heat of the waste gases for preheating the combustion air of the furnace Regenerators, however, require a system of reversing valveswhich must be attended to by an operator,and it is highly desirable to provide some arrangement which will obviate the necessity for such valves and the attention which ordinary regenerators require. have been made to devise a recuperator which would be satisfactory in practice. In this work great'difiiculties have developed since ifthe heat transmitting surface of the ture of'the preheat is limited, because the metals usually employed for this purposen'ncurnna'ronf such asheating and low, by reason of the fact that the For these reasons manyattempts burn out at high temperatures. If constructed of metals or alloys capable of with- Patented June 1, 1920. Application filed August 28, 1919.. Serial No. 820,503.

standing high temperatures, the cost of construction is largely prohibitive. If the heat transmitting surfaces are made of refrac-.

tor y material, cracks soon develop in op eration which destroy the efliciencyfof the device, since the-products of combustion and the incoming air will mix and the operation of the furnacemust be interrupted. For this reason, refractory recuperators have been limited in their use to low preheating temperatures.

My inventlon is designed to overcome these diilic'ulties and to provide a metallic recuperator capable of successful operation with relatively high temperatures.

In Fig.1 I have illustrated, largely angrammatically, one embodiment of iny invention' which will clearly illustrate its underlying principle. .In this figure the'numeral 2 designates the combustion chamber of a furnace supplied by a burner 3 and provided with a recuperator; whose coils are located in the stack 5-. The air preheated in this recuperator is conveyed to the burner 3 by means of a connectionsuch as illustrated at 6.

Roughly considered, the wallsof; the recuperatorcoils 4 have at any point 'a temperature which is midway between that of the outgoing flue gases which surround them air in the coils is preheated to only a small and of the air in said coils. As long as the amount, the recuperator pipe is kept sufiiciently cool tobe protected against burning out, but if the recuperator duct is made long, the temperature of the air toward the outgoing end becomes quite high and the duct at this part of the recuperator will be destroyed after abrief period of operation, if made" of steel-, cast iron, or any other inexpensive metallic material. There are, however, metals which will stand, very high temperatures such as platinum, nickel, chromium, or alloys of these metalsl My invention, therefore, is based upon the fact that a high .grade or highly heat resistant, metal is needed only at the outgoing end portion of the recuperator; while for the remainder of its length, a relatively cheap materlahsuh as cast iron, will answer all purposes. 3 This is illustrated in Fig. l wherethe coilia is of ordinary cast iron, while the coil 6 is of some high grade material such as nickel or nichrome, which is capable of standing high temperatures.

In accordance with my invention, therefore,

-I provide a metallic recuperator of two sec-- perature section and a low temperature sec-.

tion.

In Figs. 2, 3, 4.- and 5, I have illustrated-- another form of my invention in which the combustion chamber 2* is supplied by the burner 3 which, in turn, is supplied with its combustion air by-a recuperator located in the outgoing flue 7 of the furnace. The

air enters the recuperator at 8. This re cuperator is shown as composed of a'number of blocks or sections which can be con -veniently cast and which, after being removed, can be secured together by through bolts 9, or other suitable means. The form of these sections will clearly appear from Figs. 3, 4 and 5. The central openmgs in thesections unite to form a continuous duct for the air to be preheated, while the outer cells form flues 1O for'the outgoing products of combustion. A number of these blocks or sections at the outgoing; end of' the recuperator, such as those marked a, are 'of high heat-resisting material, such as above mentioned, while the remaining blocks or sections marked 6 may be 'oflow grade metal, such as cast v iron. Just how many sections of the recuperator or what portions thereof.

must be of high grade. metal will depend upon the temperature of the roducts of combustion when leaving the The limit is immaterial, as far as my invention is concerned.

. Instead of making the heat-transmitting surfaces at the hot end of the recuperator of a metal capable of resisting high tempera tures, I can, within the scope of my invention, construct them ofa heat-resisting .combination of refractory and metal, as

'illustrated more particularly in Fig. 1. In

this embodiment, the refractory coating 6' is exterior of the structure so that it is subjected to the flue gases, while the base metal a is interior thereof or on the .air"

side. The refractory coatingmay be. held in position in any desired and well known manner, not constituting part of the pr sent invention. In thisconstruction, if the re 'Without' makin invention readily adapts itself to'various constructions and locations of recuperators 'and is, therefore, of'wide availability.

mace and upon the temperature of preheat in the air.

fractory cracks, it. will not interfere with the operation ofthe recuperatonas the base- -metal onrtheinside will not allow the flue gas tomix with the air. The refractory coating, being held in place, will protect the metal from the excessive heat at. the high temperature position of the recuperator,

The advantages of my invention will be apparent to those familiar with this cart,

since it provides a metallic recuperator capable of giving a high preheat to the air passing therethrough without'destruction and the cost prohibitive. The

It will .be readily understood that the particular instances which I have shown are illustrative only of the principle of myinvention, and the method of construction in any givencase will differ widely therefrom,

I claim:

l 1. A recuperator having those surfaces of its low temperature section which are in contact with the air to be heated composed of a metal of low heat-resisting quality, and having those surfaces of its high temperature portionv with which the 'air to be heated con tacts of. a high'heat-resisting quality, substantiallycas described.

2. A recuperator having metallic members with which the air to be heated contacts, said members at the low tem erature portion of the recuperator being Q a low heat-resistingquality and at the high temperature portion of the recuperator .being'of a high heat-resisting quality, substantially as descrlbed.

provided with an air passage therethrough and also provided with ducts for products of combustion adjacent to the air opening,

some of said elements-having the walls of theair opening comprising a high heat-resisting metal and other of said elements having the inner surfaces of said air opening made of a relatively lower heat-resisting metal, substantially as described.

4. A recuperator having heat-transmitting 3. A recuperator having nietal elements surfaces constructed-of a metal on the air. side, andof a refractory'material on the flue gasside, substantially as described.

5; A recuperator having metallic heattransmitting surfaces, comprising metal of low heat-resisting quality at the low temperature end, and comprisin metal-lined refractory materialat the. h gh temperature end, substantially-as described. In testimony whereof I have hereunto set myhand. .oHARL s-L. W. TRINKS. 

